The Nobel Prize in Physiology or Medicine 2025 has been jointly awarded to Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi for their groundbreaking discoveries concerning peripheral immune tolerance. This crucial biological mechanism explains how the immune system prevents attacking the body's own tissues, a breakthrough with profound implications for autoimmune disease treatment and cancer immunotherapy.

The prestigious Nobel Assembly at Karolinska Institutet announced that the trio's research identified regulatory T cells—often called the immune system’s "security guards"—that maintain immune system balance and prevent autoimmune disorders such as type 1 diabetes, multiple sclerosis, and rheumatoid arthritis.

Their discoveries arrive amid growing global scientific momentum in immunotherapy and precision medicine, areas highlighted in recent conferences such as EULAR 2025 and reflected in a surge of new therapies targeting immune tolerance pathways. Emerging treatments, including CAR-T cell therapies, tolerogenic vaccines, and IL-2-based immunomodulation, are now entering clinical trials, aiming to provide more effective and safer options for autoimmune diseases and cancer.

“This year’s Nobel Prize spotlights the critical role of immune regulation in both health and disease and paves the way for next-generation therapies leveraging antigen-specific immune tolerance,” said Nobel committee chair Olle Kämpe.

The laureates hail from leading institutions in the United States and Japan. Mary E. Brunkow is a Senior Program Manager at the Institute for Systems Biology in Seattle, Fred Ramsdell serves as Scientific Advisor at Sonoma Biotherapeutics in San Francisco, and Shimon Sakaguchi is a Distinguished Professor at Osaka University.

Their work complements recent breakthroughs in autoimmune disease research, where advances in dual-pathway targeting, AI-powered diagnostics, and biologic drugs have significantly improved treatment outcomes. The discovery of peripheral tolerance has been critical to understanding how immune therapies can be designed to reset the immune system safely and effectively.

The Nobel Prize winners will share the prize money of 11 million Swedish kronor, with formal awards presented on December 10 in a ceremony marking Alfred Nobel’s legacy.